#include <iostream>
#include <string>

using namespace std;

int main(int argc, char const *argv[])
{
    
    int val_1 = 10;
    int val_2 = 20;

    int  * ptr_1 = &val_1;
    int  * ptr_2 = &val_2;

    int  * &ptr  = ptr_1;
    ptr =ptr_2;

    cout << *ptr << endl;

    return 0;
}
